title: Umchs5, a gene coding for a class IV chitin synthase in Ustilago maydis.
abstract: A fragment corresponding to a conserved region of a fifth gene coding for chitin synthase in the plant pathogenic fungus Ustilago maydis was amplified by means of the polymerase chain reaction (PCR). The amplified fragment was utilized as a probe for the identification of the whole gene in a genomic library of the fungus. The predicted gene product of Umchs5 has highest similarity with class IV chitin synthases encoded by the CHS3 genes from Saccharomyces cerevisiae and Candida albicans, chs-4 from Neurospora crassa, and chsE from Aspergillus nidulans. Umchs5 null mutants were constructed by substitution of most of the coding sequence with the hygromycin B resistance cassette. Mutants displayed significant reduction in growth rate, chitin content, and chitin synthase activity, specially in the mycelial form. Virulence to corn plantules was also reduced in the mutants. PCR was also used to obtain a fragment of a sixth chitin synthase, Umchs6. It is suggested that multigenic control of chitin synthesis in U. maydis operates as a protection mechanism for fungal viability in which the loss of one activity is partially compensated by the remaining enzymes.
authors.affiliation: Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato, Gto., México.
authors.forename: B
authors.initials: B
authors.lastname: Xoconostle-Cázares
authors.forename: C A
authors.initials: CA
authors.lastname: Specht
authors.forename: P W
authors.initials: PW
authors.lastname: Robbins
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: León
authors.forename: J
authors.initials: J
authors.lastname: Ruiz-Herrera
mesh_terms: D000595:Amino Acid Sequence; D002687:Chitin Synthase / Q000235:genetics; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000145:classification / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D015698:Genomic Library; D008969:Molecular Sequence Data; D009024:Morphogenesis; D016296:Mutagenesis; D010641:Phenotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014588:Ustilago / Q000201:enzymology / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C491360:CHS5 protein, S cerevisiae; D002687:Chitin Synthase